1. Field of the Invention
The present invention relates to a plasma reactor. More particularly, the present invention relates to a plasma reactor which can suppress deactivation of components (active components) activated by plasma when causing exhaust gas to flow through a plasma generating space to ensure efficient reaction between the active components and particulate matter, whereby the particulate matter can be efficiently purified via reaction.
2. Description of Related Art
A silent discharge occurs when disposing a dielectric between two electrodes and applying a high alternating voltage or a periodic pulse voltage between the electrodes. Active species, radicals, and ions are produced in the resulting plasma field to promote reaction and decomposition of gases. It is known that this phenomenon can be utilized to remove toxic components contained in engine exhaust gas and the like (see patent documents 1 and 2, for example).
The inventions disclosed in the patent documents 1 and 2 aim at efficiently generating radicals and the like by plasma. However, the inventions disclosed in the patent documents 1 and 2 are insufficient from the viewpoint of purifying particulate matter (PM) contained in exhaust gas.
A plasma reactor has been disclosed which includes a plasma reactor main body and a diesel particulate filter (DPF) disposed downstream from the plasma reactor main body (see patent document 3, for example). According to the plasma reactor disclosed in the patent document 3, exhaust gas is activated in the plasma reactor main body, and PM is oxidized by the activated components while trapping PM in the DPF.    [Patent document 1] JP-A-2004-27982    [Patent document 2] JP-A-2003-340272    [Patent document 3] JP-A-2004-11592